Abstract: A multi-frequency wireless access device including a first waveguide having a pair of parallel metal plates with open sides and a slot in one of the metal plates, the slot permitting radiation to leak out, the leaked radiation illuminating a range of angles depending on frequency.

Abstract: Base stations for MIMO wireless systems embodying efficient channel estimation techniques. One illustrative embodiment includes: an array of multiple antennas to exchange uplink and downlink signals with spatially-distributed user terminals; multiple transmit chains, each coupled to one of the multiple antennas by a respective transceiver that also couples that antenna to a respective one of multiple receive chains; and a controller. Each of the receive chains opportunistically derives estimated uplink channel response coefficients from packet headers in the wireless uplink signals, and the controller determines a steering transform based at least in part on the estimated channel response coefficients. The transmit chains apply the steering transform to spatially-distinct downlink signals to produce antenna-specific downlink signals for each antenna in the array.

Abstract: Base stations for MIMO wireless systems embodying efficient channel estimation techniques. One illustrative embodiment includes: an array of multiple antennas to exchange uplink and downlink signals with spatially-distributed user terminals; multiple transmit chains, each coupled to one of the multiple antennas by a respective transceiver that also couples that antenna to a respective one of multiple receive chains; and a controller. Each of the receive chains opportunistically derives estimated uplink channel response coefficients from packet headers in the wireless uplink signals, and the controller determines a steering transform based at least in part on the estimated channel response coefficients. The transmit chains apply the steering transform to spatially-distinct downlink signals to produce antenna-specific downlink signals for each antenna in the array.

Abstract: A system enhances communications security in a wireless local area network (WLAN). The system includes a multiple antenna array arranged to transmit and receive signals; and a transmitter/receiver coupled to the multiple antenna array and configured to transmit and receive the signals. The transmitter/receiver includes a beamformer, which in turn includes a signal processor component that generates a signal beam for transmission to an intended user, and a blinding component that computes one or more blinding beams using only channel state information of the intended user. The blinding beams have a zero inter-user interference condition with the signal beam.

Abstract: A method and apparatus for performing measurement-based admission control using peak rate envelopes is disclosed. A peak rate envelope estimator that uses empirical traffic envelopes of the aggregate traffic flow to allocate resources. Connection requests from the user are accepted or denied based upon the empirical traffic envelopes of the aggregate traffic flow.

Abstract: A network element is deployed in a network of interconnected elements. The network element includes a shared buffer multiplexer connected to a link, a set of regulators connected to the shared buffer mulitplexer, and an admission control unit communicatively coupled to the set of regulators and the shared buffer multiplexer. Each of the set of regulators has an input traffic flow. Each traffic flow has a varying flow rate. In order to control admission of the traffic flow to the link in the network element, the admission control unit evaluates the traffic flowing into each regulator. For each traffic flow, the admission control unit receives an envelope of the flow input to the regulator. The admission control unit maximizes the entropy of a distribution of the rate of flow over all time scales. The admission control unit determines the maximum-entropy distribution for the flow using information derived from the traffic envelope, including bounds of the mean rate, the minimum rate, and the maximum rate.

Abstract: A system and method for dynamic bandwidth allocation is provided. The method provides one or more nodes to compute a simple lower bound of temporally and spatially aggregated virtual time using per-ingress counters of packet (byte) arrivals. Thus, when information is propagated along the ring, each node can remotely approximate the ideal fair rate for its own traffic at each downstream link. In this way, flows on the ring rapidly converge to their ring-wide fair rates while maximizing spatial reuse.